I. Field of the Invention
The present invention relates generally to radar systems and, more particularly, to a radar system using forward-looking radar to detect targets.
II. Description of Related Art
Route clearance and force protection has become of paramount interest in the military, particularly in military ground actions. Currently, to detect targets, such as IEDs as well as other installations, forward-looking radar (FLR) has been used on a mobile ground mounted platform. This FLR is then used to scan the route for force protection in an effort to detect military targets.
The current FLR utilizes a high frequency radio transmitter capable of transmitting a forward-directed beam over a frequency range. This frequency range may vary from one radar system to the next, but a typical radar scanning range would be from 300 megahertz to 1.5 gigahertz. For example, for a step-frequency system, the frequency of the transmitter is incremented in fixed steps, such as 3 megahertz.
When the radar signal encounters an object, an echo is returned back to the radar system at the fundamental frequency of the radar. The distance to the target can then be determined by either time of flight, i.e. the time delay between the generation of the radar signal and the receipt of the echo, or by other means, such as FMCW which measures the frequency difference between the transmitted and received echoes.
All of the previously known FLR systems utilize the fundamental frequency of the radar transmitter to analyze the echo received by the radar system. However, natural objects, such as rocks, also produce an echo back to the radar system at the fundamental frequency of the radar transmitter. Consequently, in order to differentiate between natural objects, such as rocks, and military targets, the previously known FLR systems have utilized complex algorithms in an attempt to image process the received echo. These algorithms, however, have not proven wholly reliable in operation.